1,613 research outputs found
Association between obstructive apnea syndrome during sleep and damages to anterior labyrinth: Our experience
The obstructive sleep apnea syndrome is a chronic condition characterized by frequent episodes of collapse of the upper airways during sleep. It can be considered a multisystem disease. Among the districts involved, even the auditory system was seen to be concerned. It was enrolled a population of 20 patients after polysomnographic diagnosis of OSAS (Apnea Hypopnea Index > 10) and a control group of 28 healthy persons (Apnea Hypopnea Index < 5). Each patient has been subjected to Pure Tone Audiometry, Tympanometry, study of Acoustic Reflex, Otoacoustic Emissions and Auditory Brainstem Response. Moreover they were submitted to endoscopy of upper airway with Muller Maneuver and Epworth Sleepiness Scale (ESS). The values of ESS was 13.5 in OSAS group and 5.4 in control group. The tone audiometry is worse in all frequencies analyzed in OSAS patients, but within the normal range for both groups analyzed by 250 to 1000 Hertz. Otoacoustic emissions show a reduced reproducibility and a lower signal/ noise ratio in OSAS group (P <0.01)
Sharp interface limit for a phase field model in structural optimization
We formulate a general shape and topology optimization problem in structural
optimization by using a phase field approach. This problem is considered in
view of well-posedness and we derive optimality conditions. We relate the
diffuse interface problem to a perimeter penalized sharp interface shape
optimization problem in the sense of -convergence of the reduced
objective functional. Additionally, convergence of the equations of the first
variation can be shown. The limit equations can also be derived directly from
the problem in the sharp interface setting. Numerical computations demonstrate
that the approach can be applied for complex structural optimization problems
Singular kernels, multiscale decomposition of microstructure, and dislocation models
We consider a model for dislocations in crystals introduced by Koslowski,
Cuiti\~no and Ortiz, which includes elastic interactions via a singular kernel
behaving as the  norm of the slip. We obtain a sharp-interface limit
of the model within the framework of -convergence. From an analytical
point of view, our functional is a vector-valued generalization of the one
studied by Alberti, Bouchitt\'e and Seppecher to which their rearrangement
argument no longer applies. Instead we show that the microstructure must be
approximately one-dimensional on most length scales and exploit this property
to derive a sharp lower bound
Branching Structures in Elastic Shape Optimization
Fine scale elastic structures are widespread in nature, for instances in
plants or bones, whenever stiffness and low weight are required. These patterns
frequently refine towards a Dirichlet boundary to ensure an effective load
transfer. The paper discusses the optimization of such supporting structures in
a specific class of domain patterns in 2D, which composes of periodic and
branching period transitions on subdomain facets. These investigations can be
considered as a case study to display examples of optimal branching domain
patterns.
  In explicit, a rectangular domain is decomposed into rectangular subdomains,
which share facets with neighbouring subdomains or with facets which split on
one side into equally sized facets of two different subdomains. On each
subdomain one considers an elastic material phase with stiff elasticity
coefficients and an approximate void phase with orders of magnitude softer
material. For given load on the outer domain boundary, which is distributed on
a prescribed fine scale pattern representing the contact area of the shape, the
interior elastic phase is optimized with respect to the compliance cost. The
elastic stress is supposed to be continuous on the domain and a stress based
finite volume discretization is used for the optimization. If in one direction
equally sized subdomains with equal adjacent subdomain topology line up, these
subdomains are consider as equal copies including the enforced boundary
conditions for the stress and form a locally periodic substructure.
  An alternating descent algorithm is employed for a discrete characteristic
function describing the stiff elastic subset on the subdomains and the solution
of the elastic state equation. Numerical experiments are shown for compression
and shear load on the boundary of a quadratic domain.Comment: 13 pages, 6 figure
Neurophysiological Profile of Antismoking Campaigns
Over the past few decades, antismoking public service announcements (PSAs) have been used by governments to promote healthy
behaviours in citizens, for instance, against drinking before the drive and against smoke. Effectiveness of such PSAs has been
suggested especially for young persons. By now, PSAs efficacy is still mainly assessed through traditional methods (questionnaires
and metrics) and could be performed only after the PSAs broadcasting, leading to waste of economic resources and time in the
case of Ineffective PSAs. One possible countermeasure to such ineffective use of PSAs could be promoted by the evaluation of the
cerebral reaction to the PSA of particular segments of population (e.g., old, young, and heavy smokers). In addition, it is crucial to
gather such cerebral activity in front of PSAs that have been assessed to be effective against smoke (Effective PSAs), comparing
results to the cerebral reactions to PSAs that have been certified to be not effective (Ineffective PSAs). &e eventual differences
between the cerebral responses toward the two PSA groups will provide crucial information about the possible outcome of new
PSAs before to its broadcasting. &is study focused on adult population, by investigating the cerebral reaction to the vision of
different PSA images, which have already been shown to be Effective and Ineffective for the promotion of an antismoking
behaviour. Results showed how variables as gender and smoking habits can influence the perception of PSA images, and how
different communication styles of the antismoking campaigns could facilitate the comprehension of PSA’s message and then
enhance the related impac
Analysis of an Inverse Problem Arising in Photolithography
We consider the inverse problem of determining an optical mask that produces
a desired circuit pattern in photolithography. We set the problem as a shape
design problem in which the unknown is a two-dimensional domain. The
relationship between the target shape and the unknown is modeled through
diffractive optics. We develop a variational formulation that is well-posed and
propose an approximation that can be shown to have convergence properties. The
approximate problem can serve as a foundation to numerical methods.Comment: 28 pages, 1 figur
A Gamma-convergence argument for the blow-up of a non-local semilinear parabolic equation with Neumann boundary conditions
In this paper we study a simple non-local semilinear parabolic equation with
Neumann boundary condition. We give local existence result and prove global
existence for small initial data. A natural non increasing in time energy is
associated to this equation. We prove that the solution blows up at finite time
 if and only if its energy is negative at some time before . The proof of
this result is based on a Gamma-convergence technique
A study of methyl formate in astrochemical environments
Several complex organic molecules are routinely detected in high abundances
towards hot cores and hot corinos. For many of them, their paths of formation
in space are uncertain, as gas phase reactions alone seem to be insufficient.
  In this paper, we investigate a possible solid-phase route of formation for
methyl formate (HCOOCH3). We use a chemical model updated with recent results
from an experiment where simulated grain surfaces were irradiated with 200 keV
protons at 16 K, to simulate the effects of cosmic ray irradiation on grain
surfaces.
  We find that this model may be sufficient to reproduce the observed methyl
formate in dark clouds, but not that found in hot cores and corinos.Comment: 6 pages, 2 figures, 2 tables Accepted by MNRA
Solid microcrystalline dispersion films as a new strategy to improve the dissolution rate of poorly water soluble drugs: a case study using olanzapine
In this study, we evaluate the dissolution rate enhancement of solid microcrystalline dispersion (SMD) films of olanzapine (OLZ) formulated with four water-soluble polymers namely poly(N-vinylpyrrolidone) (PVP), poloxamer 188 (P188), poloxamer 407 (P407) and Soluplus(®) (SLP). Prepared formulations were characterised to determine particle size, morphology, hydrogen bonding interactions, thermal characteristics as well as in vitro dissolution studies conducted under sink conditions (pH 6.8). Particle size of OLZ in all formulations ranged between 42 and 58μm. Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), Differential Scanning Calorimetry (DSC) and Hot-Stage Microscopy (HSM) studies confirmed OLZ was well maintained in its crystalline state during the formulation process. In vitro dissolution studies showed immediate drug release from all formulation when compared to the drug alone. The greatest increase in in vitro dissolution rate was observed in formulations containing P188 most likely due to its enhanced hydrophilic and surfactant properties compared to the other agents used. Overall, this study successfully generated OLZ loaded SMD films with improved in vitro dissolution rates which is highly likely to result in improved oral bioavailability in vivo
Pro-apoptotic activity of the phytochemical Indicaxanthin on colorectal carcinoma cells (Caco-2) and epigenetic CpG demethylation of the promoter and reactivation of the expression of p16
Phytochemicals play prominent roles in human diet and nutrition as protective redo-active substances in prevention of several disorders and chronic diseases in humans. Today, their function as potent modulators of the mammalian epigenome-regulated gene expression is rapidly emerging. In the present study antiproliferative effects of Indicaxanthin (Ind) from the fruits of Opuntia ficus-indica (1), and potential influence on DNA methylation has been investigated on Caco-2 cells, a human cell line of colorectal carcinoma. Ind caused a clear dose- and time-dependent decrease of the cell proliferation (IC(50) 50 M) associated to apoptosis as demonstrated by phosphatidylserine externalization and depolarization of mithocondrial membrane. Ind decreased the Go-G1phase whereas increased S and G2-M phases of the cell cycle. The phytochemical did not altered the intracellular ROS levels but decreased the [Ca2+]i. Investigation on DNA methylation  using MESAP-PCR (Methylation-Sensitive Arbitrarily-Primed Polymerase Chain Reaction) (2), showed that 100 M Ind induced a slight global demethylation after a 48 h treatment. Analysis of epigenetic changes in the DNA methylation pattern at CpG promoter of p16 (INK4a), using MSRE (Methylation-Sensitive Restriction Endonucleases Multiplex-Polymerase Chain Reaction), showed that Ind caused CpG demethylation. Western blotting analysis carried out with p16 monoclonal antibody, confirmed the reactivation of the protein expression. Present data, suggesting that a long-term exposure to indicaxanthin in diet might potentially affect epigenetic machines of the intestinal cells, preventing or repairing initial derangements/disorders, encourage studies on the mechanism involved
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